Electric cable with controlled flexibility

ABSTRACT

A stranded electric cable has a plurality of flexible ropes annularly disposed and helically twisted about a core consisting of a helical spring containing a flat bar which inhibits flexing of the cable in planes of desired rigidity while permitting free flexing in a desired plane. The bar is removable and replaceable from one end without disassembling the cable and spacers are provided between the bar and the spring.

D United States Patent 1 1 3,764,724 Mulvany Oct. 9, 1973 [54] ELECTRIC CABLE WITH CONTROLLED 3,265,803 8/1966 Grove 174/15 C FLEXIBILITY 2,946,837 7/1960 Beamish.... 174/15 C 3,601,520 8/1971 Carasso 174/15 C [75] Inventor: Dale B. Mulvany, Wayne, Mich.

[73] Assignee: Watteredge-Uniflex Inc., Avon Primary Examiner-Bernard A. Gilheany Lake, Ohio Assistant Examiner-A. T. Grimley [22] Filed Jan 20 1972 Attorney-J. King Harness et al.

21 A l. N 219 392 I 1 pp 57 ABSTRACT [52] US Cl 174/15 C 174/19 174/27 A stranded electric cable has a plurality of flexible [51] Int CL d 7 B 4 ropes annularly disposed and helically twisted about a [58] Field of 16 B 28 core consisting of a helical spring containing a flat bar 130 R which inhibits flexing of the cable in planes of desired rigidity while permitting free flexing in a desired [56] References Cited plane. The bar is removable and replaceable from one end without disassembling the cable and spacers are UNITED STATES PATENTS provided between the bar and the spring. 2,985,708 5/1961 Ross 174/15 C X 3,456,064 7/1969 Toto 174/15 C X 9 Claims, 7 Drawing Figures PATENTEU 9 975 SHEET 1 [IF 2 o o o u 0 0 0 1 .0 0 0 0 0 O m\ o o o II .n o o o o I I PATENTEU W 9 I975 SHEET 2 BF 2 Jil ll ELECTRIC CABLE WITH CONTROLLED FLEXIBILITY BACKGROUND OF THE INVENTION The present invention relates to electrical conductors, and particularly to cables which are readily flexible in a desired plane but which resist bending in other planes. Such cables may be used under conditions which require them to support themselves while bent in the shape of an upstanding inverted-U and without lateral bracing, while permitting vertical movement of one of the legs of the U with relation to the other. Such an arrangement is useful, for example, in supplying electric current to the movable electrodes of electric furnaces. Although such cables must bend freely in the plane of the U, they must resist lateral bending. U.S. Pat. Nos. 2,759,988 and 3,265,803 disclose cables designed for such use.

The present invention has as its overall objective the provision of an improved cable of the general class indicated which is highly resistant to wear, which is readily assemblable and disassemblable with minimum danger of improper arrangement or orientation of the parts, and which accordingly is easy to service, and which incorporates improved liquid cooling means. Other objects and advantages will become apparent upon consideration of the present disclosure in its entirety.

BRIEF DESCRIPTION OF THE FIGURES OF DRAWING FIG. 1 is a longitudinal elevational view, with some portions broken away and shown in section, of a cable constructed in accordance with the present invention;

FIGS. 2 and 3 are cross sections on a larger scale, taken substantially on lines IIII and Ill-III of FIG. 1 respectively and looking in the direction of the arrows;

FIG. 4 is an end elevational view on a larger scale taken as indicated by the line and arrows IV-IV of FIG. 1;

FIG. 5 is a view similar to FIG. 1 showing a modified construction; the view differing from FIG. 1 also in that the ropes, although actually twisted, are shown straight for clarity of illustration; and

FIGS. 6 and 7 are fragmentary sectional views on a larger scale of the portions within the circular areas designated VI and VII respectively on FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED FORM OF THE INVENTION Reference character 10 designates a flexible hose, forming an outer jacket which at its opposite ends overlies and is secured in sealed relation to terminal connectors 12, 14 by clamping bands 18. The inserted portion 16 of each terminal is counterbored as indicated at 20 to receive the bare ends of the cable ropes 21-29, which are confined therein between the wall of portion 16 and a smaller sleeve 32 defining the inner wall of an annular pocket in which the rope ends are secured by soldering. Sleeve 32 is secured in a deeper smaller counterbored portion 30 formed at the inner end of axial water passage 34 which extends through the projecting connector portion 35 of the terminal.

A flexible filter spring 33 is fitted over the sleeve 32, between such sleeve and the cable ropes, and extends the full length of the cable inside the cable ropes, defin ing the periphery of a core area 41 and maintaining the ropes in an annular arrangement around such core area. The spring is formed of a material which will not react unfavorably (electrolytically or otherwise) such as phosphor bronze. The ropes are helically twisted throughout their length both individually and as a group, and are similarly connected to the terminal 14 at the other end of the cable. Terminal 14 is similar to terminal 12 insofar as its means for connecting the jacket, cable ropes and filter spring are concerned.

Each terminal has an outwardly extending reduced connector neck portion 35, 36 adapted to be electrically connected as may be desired. Normally, of course, one such connecting neck portion is connected to a source of power, and the other to the movable electrode of an electric furnace, or other load to be supplied with current. The axial water passages 34, 37 extend entirely through the terminals and communicate interiorly with the core space 41 within the spring 33.

In order to control and limit the lateral flexibility'of the cable by inhibiting bending thereof except in a desired plane, a relatively thin flat bar 40 which is readily flexible in one plane only is centrally positioned in the core area. The bar may be made of phosphor bronze and is of course untwisted, so that it is flat when the cable is straight. The width of the bar is slightly less than the internal diameter of spring 33. The bar is keyed to the cable structure at each end against rotation about the axis of the cable. In the terminal 14 such keying is effected by means of diametrically opposed slots 42, 43 formed in the internal wall of the axial passage 37, in which slots the bar 40 is slidably fitted. The passages 34, 37 are large enough to permit the bar 40 to be installed and removed therethrough without disassembling the terminal. Unwanted escape of the bar from the terminal 14 is prevented by a cross pin 45 removably held in the terminal by screw plugs 46.

At its outer end the connector neck 36 of terminal 14 is provided with a threaded socket portion 48 adapted to receive a coupling for a cooling water connection (not shown).

The other terminal, 12, is preferably provided with a removable keying block 50 of square external cross section, fitted in a socket 52 having correspondingly squared keying portions and opening toward the exterior of the terminal 12 and removable therefrom, with the bar, when the reducing connector housing 54 is removed. As shown in FIG. 1, the reducing bushing traps the block 50 and the bar, as well as providing for cooling water connection. At its end facing the interior of the cable core area the block 50 is provided with slots 56, 57 to receive and key the end of the bar 40 against rotation with respect to the terminal. The terminals are installed in the jacket with the slot portions 42, 43 and 56, 57 so oriented so as to lie in a common plane. The jacekt 10 and other components of the assembled cable resist torsional forces and the plane of bar 40 therefore remains fixed. The bar is slightly shorter than the distance between the bottoms of the slots 56, 57 and the pin 45, enabling the bar to float slightly longitudinally during bending of the cable."

At suitable intervals the bar is effectively centered in the spring by spacers 60 formed of a non-metallic material having good bearing properties, such as neoprene or other solid plastic. Screws 61 which secure the buttons to the bar are countersunk in the buttons so that only the buttons contact the spring. The outer ends of the buttons are partly spherical and fit the interior of the spring closely enough to convey to the spring, and thus to the entire cable assembly, the stiffening effect against lateral bends derived from the bar.

In use it is normally necessary to provide a continuous flow of cooling water through such cables, and the buttons not only center the bar, transmit reactive forces and act as effective bearings to prevent abrasive contact between the bar and spring, but also create turbulence in the cooling water, and direct a part of the cooling water outwardly through the filter spring and into intimate contact with the cable ropes, insuring passage of water between the individual strands of the ropes and thus greatly assisting the effective cooling of the cable. As shown in FIG. 1 the cable ropes may be provided with flexible jacket sleeves 64 formed of a material such as neoprene, having good bearing characteristics. The sleeves 64 are perforated to permit passage of cooling fluid therethrough.

In the modified construction shown in FIGS. 5-7, wherein parts corresponding to those of the first embodiment are designated by corresponding reference characters distinguished by the addition of the letter A, each of the terminals 12A, 14A includes a body portion attached in sealed relation to the flexible casing hose A by means of an axially directed annular groove-like area 16A, 17A into which the end of the hose projects. Cables of the class disclosed are adapted to be used in zones of relatively high temperature (e.g. 600-700F.). The hose, which may be formed of metallic strands impregnated with a heat-resistant filler, is secured by means of solder in the groove-like areas 16A, 17A. In the case of the terminal 14A the hoseretaining groove 16A is integral with the body of the terminal. In the case of the terminal 12A the groove 17A is defined by the space between the body of the terminal and an overhanging collar 70 which is applied from the smaller free end of the terminal, positioned against a shoulder 72 formed exteriorly on the terminal body, and held by the solder.

Each terminal is provided with a conductor-securing portion as 74, 75 which projects into the hose and to which the cable ropes are secured in electrically conductive relation, as by means of solder. Each of the portions 74, 75, is also provided with a central passage 34A, 37A counterbored as at 30A to receive and secure a supporting tube 32A which projects into the cable somewhat farther than outer flange portions 77-78. The stranded conductive ropes (of which only two, designated 21A, 25A, are shown) are preferably arranged helically as in the first embodiment, although shown straight in FIGS. 5-7. The ropes fit into overhanging integral flange portions 77, 78, and are held by soldering. The supporting tubes 32A define the inner walls of the conductor-securing pockets. The filter spring 33A overlies the supporting tubes and extends the full length of the cable to define the core area 41A as in the first embodiment.

The projecting portions 74 and 75 which extend into the hose 10A, are of lesser diameter than the internal diameter of the hose, so that an annular waterconducting channel 82, 83 exists around each of the portions 74, 75. Radially extending branch passages 85, 86 extend outwardly through the wall of each of the portions 74, 75 from the central water passages 34A, 37A to the exterior to conduct cooling water to and from the peripheral passages 82, 83.

A flat flexibility controlling bar A corresponding to the bar 40 previously described extends the full length of the cable between and is keyed to the two terminals 12A, 14A. The terminal 14A is shown as of the 90 type, the leg portion 88 thereof having an internal channel 87 communicating with channel 37A, and through which the cooling water may be supplied from the inlet opening 89. The channel 37A continues straight to the right extremity of the terminal, as shown in FIG. 5, where it is closed by a removable plug 90 which retains a keying block A which in turn retains and positions the bar 40A similarly to the block 50 of the first embodiment. The bar is trapped at its other end by a cross pin 45A, rotation of the bar with respect to terminal 12A being prevented by slots 42A in the wall of the terminal portion 35A. The water channel 34A of the terminal 12A is provided at its free extremity with a connection portion 54 through which the cooling water may be exhausted.

The spacers A, secured to the bar 40A, perform a similar function in preventing abrasion between the bar and spring, and in diverting the cooling water radially to insure intimate contact between the water and the conductive strands of the ropes. Such spacers are shown as positioned in an alternated relation spaced from one another on opposite sides of the bar, throughout the central part of the length of the cable. In order to increase the tendency of the cooling water to flow through the outer channel areas 82, 83, additional paired spacers as 608 may be provided in, axially aligned relation on opposite sides of the bar in the areas inside the portions 77, 78. This arrangement increases the resistance to flow through the central passages of each terminal in the regions nearer the mid-cable region than the branch passages 85, 86, thereby limiting the flow in those parts of the axial passages 34A, 37A between the branch passages 85, 86 and the cable proper, producing a greater flow and increased heatabsorbing capacity in the peripheral regions of the terminals, and affording added protection for the soldered connections in the grooves 16A, 17A, as well as the soldered areas at the rope ends.

This Detailed Description of Preferred Forms of the Invention, and the accompanying drawings, have been furnished in compliance with the statutory requirement to set forth the best mode contemplated by the inventor of carrying out the invention. The prior portions consisting of the Abstract of the Disclosure and the Background of the Invention are furnished without prejudice to comply with administrative requirements of the Patent Office.

What is claimed is:

1. In a flexible electric cable of the type having a pluralityof conductive strands arranged annularly around and extending longitudinally of a core area, a terminal at one end of the cable connected to said strands, a flexibility-controlling core assembly extending longitudinally of the cable in said core area and including a pervious flexible tubular core member and a flat bar in said tubular core member, the novel combination which comprises means for orienting the bar in the cable and for removably retaining the bar therein including a longitudinal opening extending entirely through the terminal from the exterior to the core area and of a size permitting the bar to pass therethrough, and keying portions preventing unwanted rotation of the bar with relation to the terminal.

2. A combination as defined in claim 1 including two such terminals, one at each end of the cable, at least one of the keying portions comprising a keying member which is also removable to the exterior through said opening in the terminal.

3. A combination as defined in claim 1 including two such terminals, one at each end of the cable, said means for retaining the bar including abutment portions at each end of the bar blocking the bar from moving longitudinally out of the cable through the opening, said abutment portions being spaced apart a distance somewhat exceeding the length of the bar.

4. A combination as defined in claim 1 including two such terminals, one at each end of the cable, said means for retaining the bar including abutment portions at each end of the bar blocking the bar from moving longitudinally out of the cable through the opening, said abutment portions being spaced apart a distance somewhat exceeding the length of the bar, said tubular core member comprising a helical spring, the cable having a terminal at each end and the bar being slidably keyed to each terminal against rotation about the longitudinal axis of the cable, the positioning portions comprising knob-like portions fast upon and extending radially from both sides of the bar and occupying less than the full effective internal cross section of the spring but having a clearance with respect to the spring which is less than the clearance between the bar and spring whereby when the cable is bent the knob-like portions prevent unwanted contact between the bar and spring and transmit reactive forces between the bar and spring.

5. A combination as defined in claim 4 wherein the spring is metal and the knob-like portions include nonmetallic rounded bearing portions for contacting the interior of the spring.

6. In a flexible liquid-cooled electric cable of the type having a liquid-tight jacket and a plurality of conductive strands therewithin arranged annularly around and extending longitudinally of a core area, an energyconductive terminal at one end of the cable electrically connected to said strands and incorporating liquidconducting means for feeding of liquid between the exterior and the core area, a flexibility-controlling core assembly extending longitudinally of the cable in said core area and including a pervious flexible tubular core member and a flat bar in said tubular core member, the novel combination which comprises a plurality of positioning portions extending radially between the bar and the tubular core member at positions spaced longitudinally therealong, said positioning portions occupying a substantial proportion but less than the full cross section of the area between the bar and the pervious tubular core member whereby a portion of liquid flowing longitudinally through the core area is directed outwardly toward the tubular core member and the strands by said positioning portions.

7. In a flexible electric cable of the type having a plurality of conductive strands arranged annularly around and extending longitudinally of a core area, a terminal at one end of the cable connected to said strands, a flexibility-controlling core assembly extending longitudinally of the cable in said core area and including a pervious flexible tubular core member and a flat bar in said tubular core member, the novel combination which comprises a plurality of positioning portions extending radially between the bar and the tubular core member at positions spaced longitudinally therealong, said positioning portions being held against movement with respect to the bar in directions lateral with respect to the cable and parallel to the plane of the flat surfaces of the bar, and said positioning portions being also confined against unwanted lateral movement with respect to the tubular core member.

8. In a flexible electric cable of the type having a plurality of conductive strands arranged annularly around and extending longitudinally of a core area, a terminal at one end of the cable connected to said strands, a flexibility-controlling core assembly extending longitudinally of the cable in said core area and including a pervious flexible tubularcore member and a flat bar in said tubular core member, the novel combination which comprises a plurality of positioning portions extending radially between the bar and the tubular core member at positions spaced longitudinally therealong, the positioning portions comprising knob-like portions extending radially from both flat sides of the bar.

9. In a flexible electric cable of the type having a plurality of conductive strands arranged annularly around and extending longitudinally of a core area, a terminal at one end of the cable connected to said strands, a flexibility-controlling core assembly extending longitudinally of the cable in said core area and including a pervious flexible tubular core member and a flat bar in said tubular core member, the novel combination which comprises a plurality of positioning portions extending radially between the bar and the tubular core member at positions spaced longitudinally therealong, said tubular core member being a metallic spring and said bar is a relatively flat metallic strip, the cable having a terminal at each end to each of which the strip is keyed against rotation, the positioning portions comprising knob-like portions extending radially from both flat sides of the strip and occupying less than the full internal cross section of the spring.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 724 Dated OCtOber 9, 1973 Inventor(s) AL B. MULVANY It is certified that; error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 47, "housing" should be -bushing.'

Column 2, line 56, "jacekt" should be -jacket-.

Signed and sealed this 2nd day of April 1971;.

(SEAL) Attest:

EDWARD l LFLETCHERJR. C. MARSHALL DANN Attesting Officer Commissioner of Patents FORM PO-IOSO (IO-69) USCOMWDC 603764369 U.$. GOVIINNENT PRINTING OFFICE: I969 0-366-384 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 724 Dated October 9, 1973 Inventofls) DALE B, MULVANY It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 47, "housing" should be -bushing-,'

Column 2, line 56, "jacekt" should be --jacket-.

Signed and sealed this 2nd day of April 1971;.

(SEAL) Attest:

EDWARD I I.FLEJTCHER,JR. G. MARSHALL DANN Attesting Officer Commissioner of Patents FORM PO-105O (IO-69) USCOMM-DC 60376-F'69 U.$. GOVERNMENT PRINTING OFFICE: I96! 0-366-334 

1. In a flexible electric cable of the type having a plurality of conductive strands arranged annularly around and extending longitudinally of a core area, a terminal at one end of the cable connected to said strands, a flexibility-controlling core assembly extending longitudinally of the cable in said core area and including a pervious flexible tubular core member and a flat bar in said tubular core member, the novel combination which comprises means for orienting the bar in the cable and for removably retaining the bar therein including a longitudinal opening extending entirely through the terminal from the exterior to the core area and of a size permitting the bar to pass therethrough, and keying portions preventing unwanted rotation of the bar with relation to the terminal.
 2. A combination as defined in claim 1 including two such terminals, one at each end of the cable, at least one of the keying portions comprising a keying member which is also removable to the exterior through said opening in the terminal.
 3. A combination as defined in claim 1 including two such terminals, one at each end of the cable, said means for retaining the bar including abutment portions at each end of the bar blocking the bar from moving longitudinally out of the cable through the opening, said abutment portions being spaced apart a distance somewhat exceeding the length of the bar.
 4. A combination as defined in claim 1 including two such terminals, one at each end of the cable, said means for retaining the bar including abutment portions at each end of the bar blocking the bar from moving longitudinally out of the cable through the opening, said abutment portions being spaced apart a distance somewhat exceeding the length of the bar, said tubular core member comprising a helical spring, the cable having a terminal at each end and the bar being slidably keyed to each terminal against rotation about the longitudinal axis of the cable, the positioning portions comprising knob-like portions fast Upon and extending radially from both sides of the bar and occupying less than the full effective internal cross section of the spring but having a clearance with respect to the spring which is less than the clearance between the bar and spring whereby when the cable is bent the knob-like portions prevent unwanted contact between the bar and spring and transmit reactive forces between the bar and spring.
 5. A combination as defined in claim 4 wherein the spring is metal and the knob-like portions include non-metallic rounded bearing portions for contacting the interior of the spring.
 6. In a flexible liquid-cooled electric cable of the type having a liquid-tight jacket and a plurality of conductive strands therewithin arranged annularly around and extending longitudinally of a core area, an energy-conductive terminal at one end of the cable electrically connected to said strands and incorporating liquid-conducting means for feeding of liquid between the exterior and the core area, a flexibility-controlling core assembly extending longitudinally of the cable in said core area and including a pervious flexible tubular core member and a flat bar in said tubular core member, the novel combination which comprises a plurality of positioning portions extending radially between the bar and the tubular core member at positions spaced longitudinally therealong, said positioning portions occupying a substantial proportion but less than the full cross section of the area between the bar and the pervious tubular core member whereby a portion of liquid flowing longitudinally through the core area is directed outwardly toward the tubular core member and the strands by said positioning portions.
 7. In a flexible electric cable of the type having a plurality of conductive strands arranged annularly around and extending longitudinally of a core area, a terminal at one end of the cable connected to said strands, a flexibility-controlling core assembly extending longitudinally of the cable in said core area and including a pervious flexible tubular core member and a flat bar in said tubular core member, the novel combination which comprises a plurality of positioning portions extending radially between the bar and the tubular core member at positions spaced longitudinally therealong, said positioning portions being held against movement with respect to the bar in directions lateral with respect to the cable and parallel to the plane of the flat surfaces of the bar, and said positioning portions being also confined against unwanted lateral movement with respect to the tubular core member.
 8. In a flexible electric cable of the type having a plurality of conductive strands arranged annularly around and extending longitudinally of a core area, a terminal at one end of the cable connected to said strands, a flexibility-controlling core assembly extending longitudinally of the cable in said core area and including a pervious flexible tubular core member and a flat bar in said tubular core member, the novel combination which comprises a plurality of positioning portions extending radially between the bar and the tubular core member at positions spaced longitudinally therealong, the positioning portions comprising knob-like portions extending radially from both flat sides of the bar.
 9. In a flexible electric cable of the type having a plurality of conductive strands arranged annularly around and extending longitudinally of a core area, a terminal at one end of the cable connected to said strands, a flexibility-controlling core assembly extending longitudinally of the cable in said core area and including a pervious flexible tubular core member and a flat bar in said tubular core member, the novel combination which comprises a plurality of positioning portions extending radially between the bar and the tubular core member at positions spaced longitudinally therealong, said tubular core member being a metallic spring and said bar is a relatively flat metallic strip, the cable having a teRminal at each end to each of which the strip is keyed against rotation, the positioning portions comprising knob-like portions extending radially from both flat sides of the strip and occupying less than the full internal cross section of the spring. 